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Abstract

Prosodic Entrainment Influences Subsequent Sentence Comprehension

Delta-band oscillations facilitate speech processing by synchronizing to speech prosody. In a series of behavioral studies, we observed that rhythmic prosodic contours can trigger downstream effects, affecting the comprehension of upcoming sentences. Therefore, potentially via entrainment, delta oscillations could inherit a stimulation frequency to persist after stimulus offset. To support this interpretation we conducted an MEG experiment.
We combined an initial prosodic rhythm with a subsequent visual target sentence. Target sentences were either long or short (e.g., “Max sees Tom and Karl laughs” vs. “Max sees Tom and Karl”). In a 2 × 2 design, these were combined with previously presented long or short prosodic contours. We hypothesized that delta-band oscillations would entrain to the rate of the contours and that this frequency would still be detectable in the MEG for the visual target sentence.
In the entrainment part, we observed coherence with the prosodic contour at the stimulation rate over all MEG sensors. Coherence indeed persisted into the target part with an anterior shift of the topography. Critically, when long contours were followed by short sentences, a P300 ERF was observed at the offset of the short sentence—likely indicating an omission response under the expectation of a long sentence.
Together with our behavioral results, we conclude that sustained prosodic entrainment affects subsequent sentence comprehension, with the stimulation frequency being conserved by brain areas associated with higher-level linguistic processing.